Fuel metering system and housing for same



, 1938. A M, STARR -2,105,100

FUEL METERNG SYSTEM AND HOUSING FOR SAME Filed Dec. 2, 195,5

INVENTOR.

' ATTORNEY.

Patented Jan. l1, 1938 NiTED STATES ifi-ics 2,105,100 t i' l.

FUEL METEBING SYSTEM AND HOUSIN FOBrBAME Allan M. Starr, Piedmont,Calif., assigner, by mesne ents, to Starr & Swectland, a copartnershipcomposed oi' Ernest J. Sweetland and' Allan M. Starr as copartners,Piedmont, Calif.

Appiiceuon December 2, 1935, seriei No. saisi 3 claims. (ci. 12s-131) linvention, serial No. 638,666 med october 21,

This invention is acontinuation in part of my 1932 titled Internalcombustion engine and re-v lates to fuel metering systems and housingsfor ing means of forming a iuel conduit and connections between the twomembers of the valve block.

Referring to Figure 1 in deieii i is a nencini;v provided with tappedopenings 2 `to receive cap screws for securing the cover 2| (Fig. 2) inplace.

The housing is divided by the partition 3which is provided with drilledand reamed openingsto receive the cam-followersjl, 4a and'4b. At the 5same. sides of the housing are suitableopenings to re- 5 In theoperation 0f internal iioliibusticn en ceive the ball bearings. 5 and 6,and in these bearg'ines usingl the inleetlen SYStem 0f intfeduclug ingsis mounted the shaft 'I which carries the the fuel inte the cylinders itis essentiel t0 meter cerne a, l2 end u. 'rire shaft 1 is driven inproper the fuel With extreme accuracy iut individual timed relation withthe engine through the gear Charges for the cylindersv T0 mcctthe futureI6 and pinion il. The shaft 21 which drives the l0 demanded the industrySuch au apparatus uct pinion I1 also drives the eccentric mechanism I8only must be accurate and dependable, but must which actuates theInstanv 23 of the pump. t9 be of a construction that lends itseli' toquantity which draws vfuel from the tank 22 through pipe production 0nan economical baSiS- It is also 22a and forces it under suitablepressure into the of great importance to provide e constructiveaccumuieior tank 25 through conduit 29. 'rank wherein the Vital -Del'tSare Well Druteeted, and 25 is provided with pressure gauge 26. The nu-.at the" same time are easily removable for repair mera] 23 representsan unloading, or relief valve, or replacement. It is an object ofthepresent which discharges the surplus capacity of the A invention to meetthe foregoing requirements as pump through conduit 24 into supply tank22 Well as the Objects mure Speelclly' Set forth 8S after the desiredpressure has been reached in 20 follows: l tank 25. To provide ametering mechanism wherein a Resting upon the partition 3 of the housingis metering chamber is provided with a movable what I term tire block ofthe metering mechapartitiOn the movements 0f which are cuntl'lled nlsm.This comprises two sections 32 and 33 25 directly by the Operator 01' agOVemOI- which are preferably made of hardened steel. 25

T0 DIOVlde a huSing fOr a metering lneehil- The dowels 45 and 46 serveto align the blocks 32 nism which Serves t0 proteetlit. and at the Sameand 33 while they are being secured in place. The timeeooperates tosecure theparts of the meehaparts 32 and 33 while in the casing are heldniSln tgether t0 reSiSt the internalA Pressure 0f ltightly together bymeans hereinafter described, the liquid being metered to form afluid-tight joint between their'ground 30 T0 PrOvlde a fuel meteringmechanism having and lapped surfaces along the line 4T; but they apluralltyf Puppet Valves munted in a bleek may readily be separated whenremoved from the ofmetal which is readily separableinto 'two 0r casing.The valves and springs within the block mere Darts t0 facilitatemanufacturing and eil-Se are therefore readily accessible as soon as ther 35 Of-aceess t0 the interim' Darts. block is removed from the housing.35

T0 Provide a metering mechnisln and housing The inlet tting Il isprovided with passageway fOr'Salne Wliel'ein conduits in the meteringmeeh- 42 which aligns with conduit 43 to provide en-' anism align withopenings in the housing to protrance of the incoming fuel into chamber44, and Vide fluid clinneetions and @Operate Wlthmeuns the chamber 38communicates with the injector 4o whereby the mechanism is secured inplace: vaive chamber 4s ihrough conduit 31, and conduit 40 Other objectswill be understood from the fol- 49 communicates with chamber 5I of thenext lowing description and the accompanying drawinjector valve.. ing,0f which The mechanism herein shown is designed for Figure 1 iS a SideeleVatiOn Partially in Seetiena two cylinder engine; but it will beunderstood 445 Figure 2 is a sectional elevation on vthe lines that thesame principles apply for any number oi 2-2 of Figure 1. cylinders byproviding the number of injector Figure 3 shows screw means ofcontrolling the valves and cams to suit the number of cylindersmovements ofthe movable partition inplace oi.' to be served. In theevent of there being more the cam or wedge meansshown in Figure 1. thantwo cylinders the next injector valve cham- 50 Figure 4 is a fragmentarysectional view showber would be connected with chamber 5| in the 50 samemanner that chamber 48 is 'connected with 5I and so on.v In the-event ofa onecylinder engine the construction wouldbe as shown except that cam 8would have but one lobe and cam I4, valve 5l and attendant parts wouldbe omitted.

ing 3| is provided to take care of any slight Each injector valve, as53, is connected by the neck 55 with the stem 53, which is lapped orotherwise closely fitted in the hole through the block 32., so that itcan slide freely up and down to open and close the valve withoutpermitting excessive leakage around the stem. However, the groove 59which leads to the drip-off openleakage that might occur.

Each injector valve is provided with a springl such as 51, to urge thevalve toward its seat and the chamber 63 surrounding the valve isprovided with the opening 64 which through the conduit 66 in the fitting65 communicates with conduit 61 which leads to an. injector nozzle (notshown).

1| is a piston, or movable partition, which is ground and lapped to aIclose sliding flt in the bushing 12 which is a free fit in the openingin the housing E. This is held in place by member i 19 which is threadedint-o the boss 8d. The piston 1| is provided with a flange 13, the lowerside of which acts as a stop to limit the downward movement of thepiston. The stem 1li, which may be integral with the piston 1i and angei3, protrudes through an opening in the top of member 1,3, and this stemthrough. contact with the sloping surface 11 of the slide 'iii governsthe upward travel of piston 1i. Through the clevis 13 the slide isconnected to a suitable throttle lever or other desired control means,either manual or automatic. The spring 15 rmly holds the piston 1| inits extreme downward position except when the pressure in chambers 38and 33a overcomes the force of the spring and causes the piston to rise.

A feature of novelty is the means I employ in making iluid connectionswith the blocks 32 and 33 from the outside of the housing, which meansalso serves the purpose of holding the blocks firmly in place. `This isaccomplished as follows: The fitting 4| abuts against a ground surface9| on the end of block 32 thereby forcing the block ilrmly against the-stop 92 and at the same time effectively connecting conduits 42 and 43to form a fluid-tight joint. Similarly the lower faces of the fittings65 and 65a are forced against the ground surface of the upper side ofthe block 33, simultaneously holding blocks 32 and 33 together andforming fluid-tight joints with the conduits such as 66. lThe blocks 32and 33 are further held by the bushing 12 the lower face of which makes-a tight ioint against the upper surface of block 33 and forms theleakproof chamber 38a.

The cam 8 which actuates follower 4 is atwolobe cam with the lobes 9-and Il set opposite each other, whereas the cams i2 and I4 each havebut a single lobe and these are set at an angle of degrees to the .lobesof the cam 3 so that the metering valve 34 is caused to open and closeprior to the opening and closing of each of the fuel injector valves 53and I4. From this it will be understood that whatever number ofcylinders the injector is designed to serve there is a corresponding,number of lobes on the cam 8, and that thecams controlling injectioninto the engine cylinders have their lobes disposed intermediate ofthelobes of the cam 3 which may be called the metering cam.

. As the parts in Fig. 2 bear` numerals corresponding to those used onsimilar parts in Fig.

, 1 the -funeuons or theparts snwn m this figure will be understoodFigure 3 shows a modied form of control that may be used in place of themechanism shown in Fig. 1. In this figure the' upward movement of thepiston. or movable partition 1| is controlled by the rod 35 the upperportion of which is provided with a thread which raises or lowers therod when it is caused to rotate bythe lever 91. This lever may beconnected by any suitable means to a pedal or hand lever, or to anautomatic control mechanism.

. Figure 4 is a fragmentary portion of a vertical section correspondingin position to the section illustrated in Figure -2. This viewillustrates a modified means of forming fuel conduits for conveying fuelfrom the chamber 3S (Figure l) to chambers such 'as 48 and 3i underneaththe inlector valves. In this modified form the block 33 is provided witha groove or channel iti which is milled lengthwise into the surface ofthe block and by means of a lateral channel represented by thedottedline |32 connects with the metering valve chamber 3d. In the lower block32 a vertical conduit W3 opens into the channel lili and by means of thelateral conduit |04 communicates with the chamber 4d. When thisconstruction is used, the channel @di ex? tends along the valve block toa point opposite the last valve in the series, and conduits such as |03and |34 form communication with each of the chambers such as. 43 and 5i.This arrangement of conduits, coupled with the distributing channel IDIand the connecting channel i U2 takes the place of and serves the samepurpose as conduits 31 and in Figure l and has certain structuraladvantages from a production standpoint. 'I'he ground surfaces whichform a joint between the blocks 32 and 33 cooperate to make the channelsIM and |ll2v a leak-proof conduit when the parts are tightly heldtogether by means of the screw fittings such as 65, and the bushing li.

The operation of the injector and attendant parts is as follows: Thepump i9 draws the liquid fuel from supply tank 22 through pipe 22a andforces it through conduit 29 int'o accumulator tank 23. I'he pressure intank 25 is governed by the setting of the relief valve 23 which isadjusted to suit the requirements of the engine being served by theinjector. This pressure may be of -the order of two thousand pounds persquare inch; but my system is applicable to both higher and lowerpressures. Through the conduit 3| which is in open communication withconduit 23 the fuel is conducted through conduits 42 and 43' intochamber dd.

In a four cycle engine the shaft 'i is geared to make one revolution forevery two revolutions of the crank shaft so that a charge of fuel ismetered through each of the conduits @l and 61a at alternate intervalsfor each revolution of the shaft 1. When the lobe of the cam raises thefollower 4 the valve 34 is opened, admitting Vfuel under pressure intothe chamber 33 which is in open vcommunication with chamber 36a. Sincethe pressure of fuel against the lower face of the piston. or movablepartition, 1i exceeds the pressure'exerted by spring A1i, piston. it israised until the top of rod 14 contacts with the sloping surface 11 ofthe slide 16 which acts as a stop and prevents further rise of piston1i. The lobe 3 quickly passes from under the iollower 4 when the spring3l assisted by the pressure within chamber 33 causes the valve 34 toclose. At this phase of the cycle the piston 1| is raised and thedownward pressure of spring 76 tt maintains a pressure upon the fuel. inchambers 3@ and 38a. As the rotation of the shaft 'f progresses the lobeIof the cam i2 causes the valve 63 to'open relieving the pressure incham- 'ber 38 which instantly results in spring 15 forcing piston Hdownwardly to the end of its stroke, where it is stopped by the flange13 seating against the top of the bushing 12. 'Ihisflrapid downwardmovement of piston 'H forces a nicasured charge of fuel through theconduits 6E, Bt and 6l to be sprayed into the engine combustion chamberthrough any suitable type of injector nozzle which may be of thespring-loaded type, or any other appropriate variety.

Following the closing of valve t3 the lobe il of cam 8 opens themeteringvalve 84 admitting another charge into chamber 38, again causing thepiston Il to rise. This in due course is followed Y by lobe I liftingthe follower Ib to open the valve 54 when the piston 1I is again forceddown by the spring 15 to force a measured charge of fuel through conduit61a to its associated in-v piston 1|.

. `I3 lifted o3, when all of the valves are ex-Q In modern multiplecylinder internal combustion engines it is highly desirable to supply ametering system in compact form, with few high pressure fittings notonly for economy of manu- -facture and convenience in installation. butbecause it is necessary that the conduits connecting the various partsbe as short as possible. In my novel arrangement this object is fullyrealized, and at the same time the two-part block which carries thevalve members greatly facilitates lapping the openings for the valvestems `and grinding of the valves. Furthermore, all of the valve partsare contained in the two-part block unit which `is interchangeablewithother similar units whereby replacements can be made with a minimumdelay inv operation of the power plant. When it is desired to grind thevalves the block unit is removed from the housing, the upper block V.thenecessity of `any. threaded openings in the blocks.A

s fuel will have as little eifect as possible on the operation of thesystem. By grouping' lthese valves'all into one block as shown in thedrawings It is essential that the passages from the 'accumulator 2li tothe valve 34 and the passage between valves 34, ll and ill be as shortas'possible so that the inertia, and the elasticity of the the passagesare very -s'hort and as there are -no nttings. the volume of fuelbetween the valves is .very small. Therefore the nvel and compactarrangement of the two part block held together by the fittings throughthe case is a very important feature of this fuel system.

able partition ('il) I do not limit myself to this form, and I maysubstitute in its place a dia-` phragm or other form suited to therequirements as set forth.

li claim:

l. A fuel metering mechanism comprising a casing: a horizontal partitionto divide said casing into two compartments; a cover plate substantiallyat right angles to said partition; a cam shaft mounted within one ofsaid compartments; a valve housing and valves removably mounted in theother of said compartments; a plurality. of cam followers mounted insaid partitionto form an operative connection between said cams and saidvalves; conduits in said valve housing controlled by saidvalves; screwoperated clamping means passing through said casing to. clamp said valvehousing in operative position; conduits through said screw operatedclamping means to align with conduits in said valve housing wherebyclamping said housing in operative position within said casingautomatically connects the Y i conduits in said valve housing with theconduits in said screw operated clamping means.

2. :A fluid metering mechanism comprising a housing; a partition in saidhousing; a cam shaft' on one side of said partition; a plurality of camfollowers slidably mounted within said partitionl of metering valvesmounted in said block'in operative alignment with said cam followers;screw means for securing said block in said housing; an opening in saidhousing to receive a cylindrical casing; a metering piston slidablymounted in Y said casing; means exterior to said housing to secure saidcasing in sealed union with said block.

3. A fluid metering mechanism comprising a housing; a fiuid-tightpartition to'separate said housing into two distinct parts; a cam shaftwith cams in one of said parts; aplurality of` cam fol- -lowerssiidablyf mounted in said partition and communicating with the otherpart of said nousr ing; a fluid metering block having a plurality. ofvalves mounted in operative alignment with said followers on the side ofsaid partition opposite said cam shaft; a cover plate forming a joint`with one side of said housing; a ground surface on one side of saidfluid metering block substantially in alignment with the valves therein;a plurality of screw fittings threaded through a wall of`said housingfor securing said metering block in position, certain of said fittings'being provided with fluid conduits whereby iluid connection isautomatically made with said block when same is tightened into place bysaid screw fittings.

4ALLAN M. eraan.

